From f1989ce6361193f1e213cb0b17e7dab4f2a8451c Mon Sep 17 00:00:00 2001
From: Gareth Bowen <gareth@medicmobile.org>
Date: Fri, 13 May 2016 20:56:20 +1200
Subject: [PATCH] (#5145) - Update checkpoint even when no changes

* (#5145) - Update checkpoint even when no changes
* (#5145) - Fix eslint
* (#5146) - Test requested parameter, couchdb 2 compatibility
* (#5145) - Tidy up test to be more promisey
---
 src/replicate/replicate.js            | 34 +++++++++++++------
 tests/integration/test.replication.js | 49 +++++++++++++++++++++++++++
 2 files changed, 73 insertions(+), 10 deletions(-)

diff --git a/src/replicate/replicate.js b/src/replicate/replicate.js
index a1a84d9854..62426736c1 100644
--- a/src/replicate/replicate.js
+++ b/src/replicate/replicate.js
@@ -121,11 +121,7 @@ function replicate(src, target, opts, returnValue, result) {
       }
       currentBatch = undefined;
       getChanges();
-    }).catch(function (err) {
-      writingCheckpoint = false;
-      abortReplication('writeCheckpoint completed with error', err);
-      throw err;
-    });
+    }).catch(onCheckpointError);
   }
 
   function getDiffs() {
@@ -294,15 +290,33 @@ function replicate(src, target, opts, returnValue, result) {
     if (changes.results.length > 0) {
       changesOpts.since = changes.last_seq;
       getChanges();
+      processPendingBatch(true);
     } else {
-      if (continuous) {
-        changesOpts.live = true;
-        getChanges();
+
+      var complete = function () {
+        if (continuous) {
+          changesOpts.live = true;
+          getChanges();
+        } else {
+          changesCompleted = true;
+        }
+        processPendingBatch(true);
+      };
+
+      // update the checkpoint so we start from the right seq next time
+      if (!currentBatch && changes.last_seq > last_seq) {
+        writingCheckpoint = true;
+        checkpointer.writeCheckpoint(changes.last_seq,
+            session).then(function () {
+          writingCheckpoint = false;
+          result.last_seq = last_seq = changes.last_seq;
+          complete();
+        })
+        .catch(onCheckpointError);
       } else {
-        changesCompleted = true;
+        complete();
       }
     }
-    processPendingBatch(true);
   }
 
 
diff --git a/tests/integration/test.replication.js b/tests/integration/test.replication.js
index 37d5cf4fc5..358453dcd8 100644
--- a/tests/integration/test.replication.js
+++ b/tests/integration/test.replication.js
@@ -1548,6 +1548,55 @@ adapters.forEach(function (adapters) {
       });
     });
 
+    it('Empty replication updates checkpoint (#5145)', function () {
+      var db = new PouchDB(dbs.name);
+      var remote = new PouchDB(dbs.remote);
+      var changes = remote.changes;
+      remote.changes = function (params) {
+        changesSince.push(params.since);
+        return changes.apply(this, arguments);
+      };
+      var changesSince = [];
+      var replicationOpts = {
+        filter: function () {
+          return false;
+        }
+      };
+      return remote.bulkDocs({ docs: docs }).then(function () {
+        return db.replicate.from(remote, replicationOpts);
+      }).then(function (result) {
+        result.ok.should.equal(true);
+        result.docs_written.should.equal(0);
+        result.docs_read.should.equal(0);
+        changesSince.length.should.equal(2);
+        // the returned last_seq should match the 'since'
+        // requested from remote
+        result.last_seq.should.equal(changesSince[1]);
+        // the 'since' parameter should be different on the
+        // next request
+        changesSince[0].should.not.equal(changesSince[1]);
+        // kick off a second replication
+        return db.replicate.from(remote, replicationOpts);
+      }).then(function (result) {
+        result.ok.should.equal(true);
+        result.docs_written.should.equal(0);
+        result.docs_read.should.equal(0);
+        changesSince.length.should.equal(3);
+        // the returned last_seq should match the 'since'
+        // requested from remote
+        result.last_seq.should.equal(changesSince[2]);
+        // nothing has changed on the remote so 'since'
+        // should be the same
+        changesSince[1].should.equal(changesSince[2]);
+      }).then(function () {
+        // Restore remote.changes to original
+        remote.changes = changes;
+      }).catch(function (err) {
+        remote.changes = changes;
+        throw err;
+      });
+    });
+
     it('Replication with deleted doc', function (done) {
       var db = new PouchDB(dbs.name);
       var remote = new PouchDB(dbs.remote);